1. Field of the Invention
This invention relates in general to certain new and useful improvements in container systems for the storage and transport of vegetables and, more particularly, to a container system which utilizes a reusable outer shell and at least one inner liner which contains a modified atmosphere for preserving the vegetables.
2. Brief Description of the Prior Art
While watermelons and fruits of a substantial weight are shipped in polygonal paperboard containers, such as octagonal containers, vegetables such as lettuce heads, are conventionally shipped in disposal paperboard containers which are of a rectangular construction.
Lettuce heads contain large amounts of entrained water which often leaves the head in the form of sap, or through evaporation from the leaves. This moisture penetrates the paperboard containers and can further harbor and promote bacterial growth. The entrained water in the lettuce heads causes some deterioration of the paperboard container during transit and shipment, and therefore, the containers themselves must be of a fairly thick and substantial construction. This results in a fairly significant cost for each container which thereby adds to the overall cost of shipping lettuce and similar good products.
In many cases, the lettuce and similar food products must be shipped for some substantial distance and, as a result, the containers are required to maintain their structural integrity for the transit period, which could be as much as four to six days. Since the containers are usually penetrated by water and/or sap at their destination, they are no longer available for reuse and must be destroyed.
In the prior art, when rectangularly-shaped shipping containers are taken out to a field and filled with lettuce, they usually assume a substantial weight in the range of several hundred pounds or more. Consequently, each of these containers must be sturdy and moreover, they must be located on wooden pallets for purposes of moving the same. Usually, the pallets are moved by forklift trucks. Furthermore, the container ends are sealed with staples. As a result, the containers themselves are often punctured by nails on the pallets and clearly the staples which secure the container ends may project into the interior space of the container. Since the containers are often moved from trucks to processing stations, there is a substantial amount of handling involved in the processing and transport of these containers of lettuce. This continuous handling and rough treatment lends to the early fatigue of the paperboard container, further militating against its reuse.
It is well known that the heads of lettuce deteriorate rapidly in the presence of oxygen. It would therefore be desirable to store and transport the lettuce in an oxygen-free environment. There have been attempts to package heads of lettuce in relatively small quantities (e.g. six heads of lettuce) in a plastic bag which is sealed with an inert atmosphere, such as carbon monoxide and placed in a rectangular cardboard container for shipping.
While this packaging of a small quantity of lettuce is effective for six or eight heads in a plastic bag, it has not been applicable to shipment of lettuce in large quantities as, for example, a transport container in which several hundred heads of lettuce may be stored in a single container. It was always assumed and correctly so, that the rough handling to which the large transport containers are subjected would quickly damage any plastic bags if the staples of the containers themselves did not damage and rupture the plastic bag.
When lettuce reaches its destination, as for example, a regional processing facility, the lettuce must again be peeled so that the outer layers or leaves are removed. Usually, the outer layers, when contacted by air, turn brown or wilt and dehydrate fairly quickly. After several days of exposure, many of the outer leaves are unusable and have an unsightly appearance. Consequently, these outer leaves must be manually removed. It has been estimated that as much as one-third of each head of lettuce is removed before it is rendered usable, either by the processor, a restaurant or for display in a grocery store or other location. Consequently, it is reasonably for one-third of the cost of the lettuce is wasted, not to mention the cost of the transport for that wasted lettuce.
Closely related to the problem of wasted lettuce leaves is the attendant labor costs required for removing the outer leaves of each head of lettuce. In some locations, there is an abundance of available low-cost labor, such as in farm communities where the lettuce is processed and packaged. However, when the outer leaves of the lettuce are manually removed at a different site, as for example, in a city, labor cost is substantially higher. As a result, in many cases, high-cost labor is used to perform the menial task of removing leaves of lettuce from each of the heads.
Many institutions such as regional salad processing facilities or restaurants would desire heads of lettuce which are totally usable in a form as packaged. Consequently, it would be desirable to "core" the lettuce, that is to remove the lettuce core before shipping. Again, coring of the lettuce at a farm-site community results in a much lower labor costs than which would be incurred for coring of the lettuce at a destination. Nevertheless, even when the lettuce is cored, the necessity of removing the outer leaves still arises. There is a substantial need for some means to ship lettuce in an environmentally protected container such that the lettuce will not deteriorate even when stored or transported for four to six days or more.